Sin and Virtue
by Trilies
Summary: Chikusa is a young priest and, more importantly, an exorcist whose skill can't be denied. Yet instead of keeping demons away, it seems to have drawn the attention of one in particular instead... One who wants to break his quiet apathetic facade and draw him to his knees. Priest/Demon AU, cowritten.


As a whole, the human species is boring.

They live, bend, and break in predictable ways. Give them a bit of wishful temptation, promises made of lies, and a weapon, and they'd kill their whole family for money, fame, a scrap of bread.

Those with supposed intelligence are just as easy to con. If one told them that you could help them pierce the veil between life or death, they'd become a demon's puppet so easily. Tell them that you could give them the secret to eternal life, well, they would sign their soul over without even needing to hear the rest. Simply to appear before them is often enough to make them believe they are chosen and special, and they'd work themselves to death doing his bidding.

Currently, he's been keeping a close eye on a newly minted priest- tall, pretty, and whose skills in exorcism are so impressive that already a price is on his head in the demonic underworld. That alone has been enough to draw his curiosity, and he has been indulging since then by putting little whispers into the young priest's ears now and again. Nothing too extravagant. But now, well. He wanted to meet him, to see how he would react.

So he had possessed the priest's teacher, and, over the long weeks, had slowly gotten more and more comfortable in the man's skin. Humans aren't meant to be vessels for demons. Most of the time, the infernal essences of the demonic eat away at the earthly bonds which make up human beings- vinegar gnawing at an egg shell. So the teacher's body and mind had started to go, to the point where even the Pope was willing to agree to an exorcism. It wouldn't do after all, for one of their high ranking patriarchs to be crawling along ceilings, slaughtering believers, and shrieking blasphemy as his head spun on his body.

They had gotten smart enough to try to restrain the patriarch, at the very least.

"Kill me before I commit more sins." His breath is raspy, torn, as he slumps into the seat they have him in. Uninterested, Mukuro hovers over his shoulder and watches him suffer.

It's not him he's here to see.

Footsteps clicking and beating against the stone hallway just outside the door draw his attention, and he promptly begins to slip into the man's body, his own scrunching in distaste. Possession is a downgrade for him, having to try to fit all of his being into an unsatisfying sack of flesh that feels like it's practically covered in dirt and full of maggots. Every single sense of his is blunted heavily, and even his impeccable mind feels slowed, stunted. It's been centuries since he had bothered with it last, more than capable of driving people mad without ever showing his face, so to speak...

...But this one might be worth the effort.

* * *

In a way, the only surprising thing in this whole endeavor is the... indirect way things have been happening.

This is not the first time Chikusa has had to deal with demonic forces. To be accepted as a priest himself, capable of guarding the flock and guiding it, confronting a demon had been one of his tests. The affair had taken place in a simple blank room, his teacher behind him and the possessed soul in front, and he had done his duty has had been required of him. The many hisses, whispers, and snarls had threatened to drown out the sound of his own soft voice, but he had persevered.

They say you never forget your first. However dark the situation might have been, Chikusa supposes that's true. He still hasn't forgotten a single detail of that day.

Perhaps because of that, when his hair had risen on the back of his neck and he could almost feel lips along the curve of his ear with words on the edge of his hearing... Well. There weren't many other things it could have been. Dutifully, since then, he has done his prayers and prepared for any number of scenarios including possession of his own body. He'd... almost been fascinated at the idea, in the detached way he views so much still. Nowhere in his studies has there ever been mention of what it's like to be possessed, and he has never heard his teachers mention it of their own accord. Is it uncomfortable, painful? Or is it simply nothing at all? There has only ever been the effects and changes one could notice in one possessed. With this possibility, he could experience the answer firsthand. Perhaps, he supposes, similar to the fascination of one wondering what a broken limb felt like.

So for his teacher to be the one to be taken is almost a shock. Almost.

There's no trace of that on his face as he enters the room, however. No grief, no shock, no anger as his eyes fall upon the poor soul restrained tightly in the chair. Behind his back, when they think he can't hear, he's heard other priests and parishioners alike say he's as quiet and emotionless as a doll. Perhaps it's true. he certainly looks it, he knows, with pale skin all the paler between his cassock and black hair making him near monochrome. The only sign of color is the purple stole hanging from his shoulders and the dull color of his eyes that matches.

Dutifully, he crosses himself, but, instead of shifting into the ages long Litany of Saints, Chikusa stares over at his former teacher.

Is this the same creature that's been bothering him for so long, targeting now one of the only people he has any connection to? Is it arrogance to suspect so? Well, regardless, his job is the same. He starts turning to the appropriate pages in his Bible.

"...If you could surrender your name and leave this man's body, it would save us all the effort." It's a quiet bland statement, as if this occurrence is that of the mundane instead of the supernatural, and his teacher isn't looking more like a corpse than a living person. Oh, by all means he'll do all the prayers no matter the answer. You can never be too safe, and never too distrustful of the words of demons. It's just... What a tiresome and troublesome thing. He doesn't want this creature to believe that it's worth the time of God, whose power he's calling upon.

Before him, his teacher's body moves slowly, carefully. Each movement is with purpose, even if it is to move the head slightly from side to side as if taking care of some ache. Only then did the face contort into a smugly amused expression, a soft chuckle escaping that nonetheless shook its shoulders. "Kufufu, I apologize for having to disappoint you, but since it took effort to get here, I would like some effort to be made before I'm sent back."

There can be no doubt... It must be a demon. The voice that escapes from his mentor may be from the same voice box, but it's completely and utterly different. Too smooth, a soft and slow purr that pricks at the back of his neck. It's mocking, too, but in a way that's more than that. A particular cadence. Even as he picks at the idea, the body raises its head, and a pair of mismatched eyes somehow shine through his teacher's pupils.

"I'm expecting some entertainment from you, Chikusa Kakimoto."

 _Well, you're going to be disappointed then._ It flickers through his mind, a wayward breeze of a thought, before Chikusa brushes it aside.

Still, to know his name… Perhaps this is the same entity that's been quietly heckling at him for a little while now. On the other hand, demons know a lot. It's one of the ways they lure human beings into sin. They mix a frightening amount of knowledge with silver lies, tormenting the unaware. In the end, it doesn't really matter, does it?

He has a task to complete. _That's_ all that matters.

The Litany of Saints takes up a nice long while to complete- so many names to request protection from, so many deliverances to request from their Lord. In contrast to it, Psalm 53 seems blessedly (pun not intended) shorter. Chikusa recites it all with the same patient, smooth tone. Only a few times does he have to look to his Bible to refresh his memory. One last prayer, and finally… The perhaps most vital part of these proceedings. The actual confrontation.

He takes a breath, shoulders moving with the motion, before focusing on the peculiar mismatched gaze that's looking back at him. "I command you, unclean spirit, whoever you are, along with any of your minions now attacking this servant of God, by the mysteries of the incarnation, passion, resurrection, and ascension of our Lord Jesus Christ, by the descent of the Holy Spirit, by the coming of our Lord for judgment, that you tell me by some sign your name, and the day and hour of your departure. I command you, moreover, to obey me to the letter, I who am a minister of God despite my unworthiness; nor shall you be emboldened to harm in any way this creature of God, or the bystanders of this place, or any of their possessions."

Considering the demon's amused reaction from before and so many other past experiences, Chikusa doubts this will work at this stage yet. Only young and weak demons would fall to Psalm 53 so easily, and those are not the kind of demons which can possess a priest. However, that is the order of such things. A cross on his person, holy water, and his stole will all no doubt be used soon enough.

So it's a surprise when the body before him, stolen and captive, begins to quiver and objects around the room smash off of their places. Cautiously, he tightens his grip on his bible and another around his stole as a cacophonous wind suddenly twists to life. There seems to be no need, as not a hair from his head even shifts, but caution is better than recklessness, even as the demon shrieks in agony. Chikusa has seen this before, as other demons in the past have fought tooth and nail to stay on God's earth, howling from the effort, but...

Something is wrong.

Suspicious, his eyes narrow at the writhing body before him which tosses its head back to reveal wide and colorless eyes. Taking care not to show any other reaction, Chikusa merely continues beneath the sound of the screams until, finally... As the psalm nears its end, the body's head flops forward with the chin resting against its chest. Quietly, Chikusa finishes the psalm. Without his voice, the room is completely quiet- items still and unmoving where they were tossed, the wind gone as quickly as it had gone. He doesn't move.

After a few seconds, a low laughter starts.

It gets louder and louder, until the demon's body is shaking in mirth and not dramatics. Its head falls back, eyes as mismatched as they ever were, and its mouth curls upwards in a cruel smirk.

"Try the litany next. That one's my favorite." How wonderful- a demon with a sense of 'humor'. Chikusa's expression shifts back from suspicion to its usual blankness, and he reaches down to turn the page. Even as he does so, the demon continues to speak. "Or, since you're so concerned about effort, I can tell you it'll fail. Would you like to know why?"

"Not particularly," he answers dully now that the whole dramatic mess is done with. Letting go of his stole, he reaches forward to press against his former teacher's forehead. Idly, his thumb sweeps away a stray flop of hair. "They shall lay their hands upon the sick and all will be well with them. May Jesus, Son of Mary, Lord and Savior of the world, through the merits and intercession of His holy apostles Peter and Paul and all His saints, show you favor and mercy..."

Clearly that's not what the demon wants to hear, although Chikusa can't imagine what it was expecting, as it slumps back into the chair with a sigh. It must be an uncomfortable position, but it doesn't seem to care much. "Or would you be more interested in knowing why I'm here?" it tries, eyes focused on Chikusa's face intensely as if it can find something.

Well, in its own way, the reaction is a positive sign. While it's impossible to _bore_ a demon out of the body it's possessed, Chikusa imagines he would still accept it. Pain, boredom, and the will of God- that's one way to do an exorcism. Now if only the creature can stop being so talkative still... How bothersome.

He doesn't bother to answer the demon's question. Instead, he meets its eyes squarely as he traces the cross over his forehead, lips, and heart. "When time began, the Word was there, and the Word was face to face with God..." Reaching down, he starts to do the same to the possessed body.

"And the Word was God."

Yet as he tries, the demon slips a tongue out to catch at his fingers when he reaches the mouth. Chikusa can't help the way his lips twist or his nose wrinkles, and he immediately pulls his hand back. "Ἐν ἀρχῇ ἦν ὁ λόγος, καὶ ὁ λόγος ἦν πρὸς τὸν θεόν, καὶ θεὸς ἦν ὁ λόγος," the demon spits back with the mouth free, voice balancing poisonous mocking and contempt. "Words with no backing of faith mean little to me, priest. You'd have better luck regaling me with tales of your childhood." Slowly, it lowers its lashes, red eye still burning bright as it follows Chikusa's hand where he wipes his fingers against his clothing. "Or asking yourself how your beloved mentor succumbed to me so easily. Are you aware of his sins or only his virtues?"

Dirty creature. At least the solution is simple enough. Now to finish the rest of _this_ one, and he does so by finishing his recital of St. John. It's only when that's done and he's reaching for the vial of holy water he possesses does he entertain the creature with an answer. "I suppose he was weak. Either way, it's irrelevant to me."

The demon is already chuckling from the reaction to its tongue, as if that's anything to be triumphant about, and it tilts its head to the side at an actual answer. "He wasn't weak at all," it says lowly, eyes half lidded and sharp from underneath the lashes it's borrowed. "It took quite a bit of effort to get to him. Isn't that more terrifying than if he had been easily overtaken?"

"If I say yes, it's horribly frightening, will you become quiet save for the surrender of your name?" Chikusa deadpans. Unimpressed, he carries on with his duties, murmuring out a quick blessing.

"Of course I would," the demon drawls, obliging in a way that's at least 90% sarcasm and not hard to miss, "since that seems like a fair trade." As holy water is flicked across his body and face, the demon makes a face, although it's not one of pain. If anything, it's mildly annoyed as if a swarm of gnats are what's bothering it. All too soon, it's gone, and it looks up to Chikusa with a sly and amused sort of expression. "Feel free to call me Mukuro-sama. Let's get along from now on, shall we?"

Chikusa had been only a second ago close to rewarding that sarcastic reaction with more holy water and a dutiful recitation of St. Mark, but he pauses at the admission of the demon's name. In such cases, when it's not forced out of them, such names are fake. Yet this demon seems... more confident and clever than other demons Chikusa has dealt with. It's enough to make him ponder if this is perhaps a mind game, where victory relies on Chikusa assuming the name is fake.

Well, there's only one way to find out.

"Mukuro..." He sounds it carefully on his tongue, and the demon chuckles in delight. A questionable sign. Frowning a little, Chikusa asks, "Is that your true name?"

Canting its borrowed face to the side, the demon's lips curl up. "Of course not." His grin widens, and he actually has the audacity to _wink_ at Chikusa. "You forgot the '-sama'."

All Chikusa can do for a second is stare... Before, without a word, he splashes more holy water right into the demon's face.

It's not something he thinks he can regret, not when the demon is reduced to staring at him in wide eyed shock for a quiet moment. It's not in Chikusa's nature to smirk, but he thinks it's a temptation right now. Demons, in his experience, are so used to being treated with reverence and fear that they never quite know what to do in the face of such blatant disrespect from someone who can withstand it. Chikusa almost thinks that, with that, the exorcism might fall back into the usual scripts: threats to himself, or his loved ones.

To his surprise... _Laughter_ bursts out from the demon. Shoulders shaking in mirth, it tips its head back and its laughter only seems to grow louder. Chikusa stares, unsure of what to do. That had been meant to be an... insult, a dismissal, a reminder that this is a confrontation of wills and that the creature isn't wanted. This is truly like no demon he's ever dealt with before, and, in the end, all he can do is school his expression back into place as he looks down at the Bible. As the demon's torrent of laughter continues, he recites the passage of St. Mark quietly but firmly. It's right as he starts to wind down to the end of it that, too, the demon's noise begins to quiet.

As he looks up, so does the demon, still snickering with laughter. "You don't need holy water to make me wet, Chikusa Kakimoto."

For a lack of better wording: what the hell.

Most demons he's come into contact with have offered sexual services in one of two ways: the first being just crass threats more than anything, and the second being honeyed words.

This is... He's not sure what to make of this.

The long bland stare he directs down into the demon's gaze is just as blank as all the ones before it, with a hint of bewilderment somewhere in the undercurrent. "...You've been in that body for too long," he finally says softly. It's half said because that would explain the demon's ridiculousness, but also... He's correct. He's sure of it.

His teacher's body is sturdy, to have lasted under possession for this long. Demons can often be reckless with the bodies they steal, not only from doing dangerous and violent things with them, but from ignoring the basic functions of the human body. Chikusa has seen cases where humans have become emaciated after demonic possession, the infernal thief responsible having ignored food or rest. It's not only that, either. Particularly powerful and old demons seem to have a horrible effect on human bodies, wearing their unwilling hosts down sometimes to the point of death.

Not that a demon would care, of course...

Yet this particular one seems to take that into consideration. "Perhaps I should make you a bargain, priest," it says, shaking the holy water off of its face. Some still remains, sizzling off of the skin, and that only seems to annoy it more. "Let me visit you again, and I will leave your teacher be."

"I'm not giving you permission to possess me." While it might not show so obviously, something in Chikusa relaxes. There, this is what he's more used to. Deals, a silver tongue, promises. It's not... whatever he was talking about before with being wet.

Still, what a strange request. He tilts his head ever so slightly as he stares down at the demon with an analytical tint to his gaze. Is this simply an attempt to leap from one member of the clergy to the next to harm their number? Chikusa doubts he could fight against a possession so well as his teacher, but he can at least say he won't give permission.

Before he can spend too much time thinking on the question, the demon chuckles. "If I wanted to possess you, I would have done so already," it says, bored, and leans its stolen body back into the seat again. Canting its gaze upwards, it meets Chikusa's own fully. "I haven't met a human of your caliber in quite some time. I'm curious about you, Chikusa Kakimoto. Nothing more, nothing less."

That can't be the half of it; demons are never so straightforward. "Flattery isn't going to work in your favor," Chikusa murmurs, and the demon chuckles again.

"Kufufu, who said it was flattery? Demons are able to tell the truth." Before he can call the demon out on such a lie, its eyes slide halfway shut and it exhales slightly. "I would suggest you decide quickly. Your teacher is nearing his limit."

Over the many long centuries, demons have culminated a certain reputation that even most stories know of and pass on. Selective truths and sweet promises are the tools of their trade, and have made legions of people fall prey to sin and into Hell before him.

Even as he knows that, however, Chikusa is weighing over the pros and cons hastily in his mind. It would be for the best if one of the Church's patriarchs could be brought back instead of perishing. They can't afford to lose anyone, not really.

Besides... This could be a test. A way to strengthen himself against demonic forces. That was why the Lord tested people in the past, after all, to make themselves stronger. Perhaps this is a similar opportunity? To learn if nothing else. Wetting his fingers with holy water, he traces the cross over his teacher's forehead.

"...Leave this man alone for the rest of his life and afterlife, and you may visit me once in exchange, Mukuro. "

Even if demons go back on their words, this is worth a try. If it fails, well, he can stay here for as long as necessary for this exorcism.

Quiet up until this moment, the demon seems satisfied with the answer given even as holy water burns across skin. "Don't forget the '-sama' next time," he says, smug and teasing, "and we'll have a deal."

And just like that, the body goes completely and utterly limp.

* * *

Pulling himself out from the teacher's body is almost blissful, and he enjoys the feeling for what it is as every single inch of him stretches out into his full and unrestrained essence. Yet he doesn't let himself enjoy it for too long. Soon enough, his gaze falls back onto the young priest which has ensnared his attention.

Quite honestly, one of the things that had initially fascinated Mukuro so about this young priest had been his utter detachment. For how many demons he's defeated one by one, he's hardly looked ruffled by his feats. Now that he has met Chikusa Kakimoto, Mukuro can't say that such an impression is wrong. After all, in contrast to so many others, he hadn't succumbed to Mukuro's charisma- something that's as admirable as it is vexing. Yet he's also _gullible_ , or, at the very least, fun to tease. It's a direct contradiction to his outwardly normal, almost boring exterior, and it makes for quite the entertaining juxtaposition. As he's known from the start, he'd been correct after all. This mortal might be worth some of his attention.

His pursuit could easily gain him the reward circulating the underworld, but such a paltry thing... No, it doesn't have his interest. Anything that it could offer him, he knows he can take by force if the idea wasn't such a dull one. No, the idea which interests him is that of being able to have one of God's most devoted and unshakable followers crumble at his feet... Although he supposes he could settle with simply breaking the man's apathetic facade.

Yet the key to any of it had been getting the young priest to agree of his own free will. Small concessions can be piled up over time, after all. So when he'd leaned forward to trace the sign of the cross on his host's forehead, Mukuro had seen it for what it was, what it is: an opportunity. It's why he stays thick in the air of the room, curled through the small space, and smiles to himself.

For all of Chikusa's great achievements, he is alone. No one has made the effort to understand him, only to use him. At least Mukuro would have the decency to do both.

* * *

 **Author's Notes:** Cowritten with my friend Mimi, based off of a RP between the two of us.


End file.
